In vitro study on the antimicrobial activity of various antibiotics against clinical isolates of Streptococcus pneumoniae from Belgium collected during winter 1998-1999

A total of 205 isolates of Streptococcus pneumoniae obtained from 10 different centres were included in this study. The susceptibilities to penicillin, ampicillin, amoxicillin, amoxicillin/clavulanic acid, cefaclor, cefuroxime, cefotaxime, imipenem, ciprofloxacin, gemifloxacin, grepafloxacin, levofloxacin, trovafloxacin, erythromycin, clarithromycin, miocamycin, clindamycin and tetracycline were determined by a microdilution technique following NCCLS recommendations. Decreased susceptibility to penicillin was 16.1% [6.8% intermediate (0.12-1 microgram/mL) and 9.3% high-level (> or = 2 micrograms/mL)], cefotaxime insusceptibility (> or = 1 microgram/mL) 12.7%, ciprofloxacine insusceptibility (> or = 2 micrograms/mL) 15.6% with 1.5% of high level resistance (> or = 4 micrograms/mL), erythromycin insusceptibility (> or = 0.5 microgram/mL) 36.1% and tetracycline insusceptibility (> or = 4 micrograms/mL) 22.9%. Decreased susceptibility to cefotaxime was found in 78.8% of the penicillin-insusceptible isolates. No decreased susceptibility was found for gemifloxacin (> or = 0.5 microgram/mL) and trovafloxacin (> or = 1 microgram/mL). Compared to the 1996-1997 surveillance, penicillin, cefotaxime and erythromycin insusceptibility rose by 3.8%, 5.2% and 5.0% respectively, while tetracycline insusceptibility decreased with 8.2%. MICs of all beta-lactams rose with those of penicillin for penicillin-insusceptible isolates. Amoxicillin +/- clavulanate, cefotaxime and imipenem were generally 1, 1 and 5 doubling dilutions respectively more potent than penicillin on these isolates. Penicillin, ampicillin and cefuroxime were equally active while cefaclor was generally 5 dilutions less potent. Most penicillin-insusceptible isolates remained fully susceptible to amoxicillin +/- clavulanate and imipenem. The penicillin-insusceptible isolates were 36.4%, 27.3% and 3.0% co-insusceptible to erythromycin, erythromycin plus tetracycline and tetracycline respectively. A subpopulation of 52 isolates obtained from children aged < or = 3 years was also studied. Compared to the other isolates we found a statistically significant increase in insusceptibility for penicillin, cefaclor, cefuroxime, erythromycin, clarithromycin and tetracycline while a significant decrease was found for ciprofloxacin.     

Surveillance of antibiotic resistance in clinical isolates of Streptococcus pneumoniae collected in Belgium during winter 2000-2001

A total of 314 isolates of Streptococcus pneumoniae collected by 10 different laboratories were tested for their susceptibility by using a microdilution technique following NCCLS recommendations. The following antibiotics were included: penicillin, ampicillin, amoxicillin, amoxicillin/clavulanate, cefaclor, cefuroxime, cefotaxime, imipenem, ciprofloxacin, gemifloxacin, levofloxacin, erythromycin, clarithromycin, azithromycin, miocamycin, clindamycin and tetracycline. The insusceptibility rate (IR) to penicillin was 21.0% [10.8% intermediate (> or = 0.12-1 microgram/mL) and 10.2% high-level (> or = 2 micrograms/mL)], to cefotaxime 7.3% [3.5% intermediate (> or = 1 microgram/mL) and 3.8% high-level (> or = 2 micrograms/mL)], to imipenem 3.8% [3.8% intermediate (> or = 0.25-0.5 microgram/mL) and 0% high-level (> or = 1 microgram/mL)], to ciprofloxacin 11.2% [8.3% intermediate (2 micrograms/mL) and 3.9% high-level (> or = 4 micrograms/mL)], to erythromycin 30.3% [3.5% intermediate (0.5 microgram/mL) and 26.8% high-level (> or = 1 microgram/mL)] and to tetracycline 38.5% [0.9% intermediate (4 micrograms/mL) and 37.6% high-level (> or = 8 micrograms/mL)]. No decreased susceptibility was found for gemifloxacin (> or = 0.5 microgram/mL). This compound was the most active with MIC50, MIC90 and an IR of 0.015 microgram/mL, 0.03 microgram/mL and 0% respectively, followed by amoxicillin/clavulanate, amoxicillin and imipenem (MIC50, MIC90 and IR: 0.015 microgram/mL, 1 microgram/mL, 1.6%/0.015 microgram/mL, 1 microgram/mL, 1.9%/0.008 microgram/mL, 0.12 microgram/mL, 3.8% respectively). Compared to the 1999 surveillance, penicillin and tetracycline-insusceptibility increased with 4.9% and 15.6% respectively, while cefotaxime, erythromycin and ciprofloxacin insusceptibility decreased with 5.4%, 5.8% and 4.4% respectively. MICs of all beta-lactams rose with those of penicillin for penicillin-insusceptible isolates. Imipenem, cefotaxime, amoxicillin and amoxicillin/clavulanate were generally 4, 2, 1 and 1 doubling dilutions respectively more potent than penicillin on these isolates while ampicillin, cefuroxime and cefactor were generally 1, 2 and 4 dilutions respectively [table: see text] less potent. Most penicillin-insusceptible isolates remained fully susceptible to amoxicillin/clavulanate (92.4%), amoxicillin (90.9%) and imipenem (81.8%). Erythromycin-tetracycline insusceptibility was the most common resistance phenotype (14.3%). Three- and four-fold resistance was found in 12.4% and 1.6% respectively of the isolates. Most penicillin-insusceptible isolates were of capsular types 14 (22.7%), 23 (21.2%), 6 (18.2%), 9 (13.6%) and 19 (12.1%).     

High prevalence of integron-mediated resistance in clinical isolates of Salmonella enterica

Salmonella enterica has become progressively resistant to antimicrobial agents worldwide as a result of genes carried on different classes of integrons. The aim of the current study was to investigate the molecular diversity of these integrons and their association with antimicrobial resistance in clinical S. enterica isolates from Tehran, Iran. Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute. The presence of integrons was investigated by PCR using specific primers. Integrons were detected in 65 (47.1%) strains, with classes 1 and 2 being observed in 54 (39%) and 11 (8%) strains, respectively. Integron-positive isolates belonged to seven different S. enterica serovars, and all showed a multidrug-resistant (MDR) phenotype. Our findings show that integrons are widely disseminated among S. enterica strains from Tehran. Furthermore, the results that class 1 integrons were more prevalent than class 2 in Salmonella isolates, and that a statistical association with MDR patterns was observed, suggest that they are more likely to be important in conferring a resistant phenotype to Salmonella strains.     

Surveillance of antibiotic resistance in non invasive clinical isolates of Streptococcus pneumoniae collected in Belgium during winters 2003 and 2004

A total of 391 and 424 non-invasive isolates of Streptococcus pneumoniae collected by 15 laboratories during the 2003 and 2004 survey were tested for their susceptibility by a microdilution technique following NCCLS recommendations. Insusceptibility rates (IR) in the two surveys (2003/2004) were as follows: penicillin 15.0/14.7% [8.4/6.4% Resistance (R)], ampicillin 17.4/14.6% (R 9.0/7.1%), amoxicillin +/- clavulanic acid 2.6/1.2 % (R 0/0%), cefaclor 14.3/14.1% (R 11.5/13.4%), cefuroxime 13.6/12.7% (R 10.5/11.8%), cefuroxime-axetil 10.5/11.8% (R 10.0/9.2%) (breakpoints based on 250 mg), cefotaxime 4.9/6.2% (R 1.3/2.4%), ceftazidime NotTested (NT)/6.4 (R NT/2.6%), cefepime NT/6.4 (R NT/2.6%), imipenem 7.7/8.9 % (R 1.8/1.4%), ertapenem 0.8/NT% (R O/NT%), ciprofloxacin 13.8/9.0% (R 4.3/2.4%), levofloxacin 3.3/2.8% (R 1.5/0.2%), moxifloxacin 0.6/0.2% (R 0.3/0%), ofloxacin 13.5/9.0% (R 4.3/2.4%), erythromycin 26.1/24.7% (R 25.3/24.5%), azithromycin 25.4/24.7% (R 24.6/24.5%), telithromycin 0.8/0.2% (R 0.5/0%), clindamycin 21.2/18.4% (R 19.2/17.7%) and tetracycline 32.3/22.1% (R 29.2/19.3%). There were only minor differences in resistance rates according to age, sample site, admission type (i.e. ambulatory, hospitalized or long-term care facility patients), gender and geographic origin. Overall, telithromycin (MIC50, MIC90 in 2003/2004: 0.015 microg/ml, 0.12 microg/ml/ 0.008,0.06 respectively), ertapenem (0.03; 0.25/NT), moxifloxacin (0.06; 0.25/0.06, 0.12), and amoxicillin +/- clavulanic acid (0.03; 0.25/0.015, 0.5) were the most active compounds in both surveys. In 2003, the most common resistance phenotype was isolated insusceptibility to tetracycline (10.5%) followed by combined insusceptibility to erythromycin and tetracycline (9.3%). Erythromycin-tetracycline resistance (10.4%) was the most common in 2004. Isolates showing resistance to an antibiotic were significantly more present in 2003 than in 2004 (50.4% versus 40.8%). In penicillin-insusceptible isolates, MICs of all beta-lactams were increased but cross-resistance between penicillin and other beta-lactams in the penicillin-insusceptible isolates was not complete. In the 2003 survey, most of these isolates remained fully susceptible to ertapenem (94.9%) and amoxicillin +/- clavulanic acid (83.1%). In the 2004 survey, 91.9% of the penicillin insusceptible isolates remained susceptible to amoxicillin +/- clavulanic acid. In both surveys, the most common serotypes in penicillin insusceptible isolates were 14, 23,19 and 9 (20.0%, 20.0%, 16.4% and 10.9% respectively in 2003; 41.6%, 11.7%, 15.0% and 18.3% respectively in 2004).     

Comparative in vitro activity of three new quinolone antibiotics against recent clinical isolates

New orally absorbable quinolone derivatives, ciprofloxacin, norfloxacin, and ofloxacin demonstrated excellent activity in vitro against clinical isolates of Escherichia coli, Klebsiella, Enterobacter, Proteus mirabilis, Proteus sp. indole-positive, Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus, Streptococcus pyogenes and enterococci. None of the 3 drugs was more than moderately effective against Bacteroides fragilis. Ciprofloxacin was 2-4 times more effective against most gram-negative strains than was either norfloxacin or ofloxacin, and was also the most effective against gram-positive strains, though the difference was less marked. Ciprofloxacin and ofloxacin were almost equally effective against S. aureus. Results with agar and with broth were comparable. The activities of all 3 drugs were essentially independent of inoculum size, as the MIC values increased less than one dilution step when the inoculum was increased from 10(3) to 10(6). The new quinolone derivatives would appear to be promising alternatives to injectable drugs such as the aminoglycosides and cephalosporins.     

Alterations in penicillin-binding proteins of clinical and laboratory isolates of pathogenic Streptococcus pneumoniae with low levels of penicillin resistance

Several recent surveys of clinical isolates have indicated that substantial fractions of naturally occurring populations of Streptococcus pneumoniae have undergone a distinct upward move in the required minimal inhibitory concentration (MIC) of benzylpenicillin (from a range of 0.006-0.008 to 0.03-0.05 microgram/ml). Evidence is presented that in clinical pneumococcal isolates, penicillin-binding proteins (PBPs) groups 1 and 2 have a decreased affinity for radioactive benzylpenicillin as compared with penicillin-sensitive isolates from the same locale. Exposure of a penicillin-sensitive type 2 strain (MIC, 0.006 microgram/ml) to sequentially increasing concentrations of penicillin allowed the isolation of spontaneous resistant mutants with stepwise increases in the MIC of penicillin required (0.01-0.02, 0.025-0.05, and 0.1 microgram/ml), and in these laboratory isolates too, PBP groups 1 and 2 showed decreased affinity for labeled benzylpenicillin. DNA from the low-level resistant clinical or laboratory isolates could be used to transform the appropriate levels of penicillin resistance into penicillin-sensitive laboratory isolates. These findings suggest that significant fractions of natural pneumococcal populations may have acquired one or two of the low-level penicillin resistance genes.     

肺炎克雷伯菌体外耐药监测

目的 探讨肺炎克雷伯菌（KP）的分布、感染特点及其体外对抗生素的耐药情况。方法 采用纸片扩散法K-B法对武汉大学人民医院临床分离的130株KP进行耐药性检测，并用双纸片协同法初筛、确证法检测产超广谱β-内酰胺酶（ESBLs）菌。结果 130株KP主分布于呼吸内科，并以第二季度最多；对氨苄西林的耐药率高达95．31％，对第三代头孢菌素类抗生素的耐药率为41．27％～52．46％；最敏感抗生素为亚胺培南。产ESBLs肺炎克雷伯菌检出率为29．23％。结论 肺炎克雷伯菌对抗生素的耐药性日趋严重，临床实验室应常规检测其是否产ESBLs。     

Determination of penicillin resistance in Streptococcus pneumoniae isolates from southern Brazil by PCR.

OBJECTIVE: To demonstrate the potential clinical applicability of the PCR technique to the early detection of bacterial resistance in Streptococcus pneumoniae. METHODS: We studied 153 samples of S. pneumoniae, isolated from different anatomic sites, using polymerase chain reaction (PCR) for the detection of specific amplicons from genes that code for penicillin-binding proteins (PBP) 1a, 2b and 2x, which are responsible for penicillin resistance in this organism. The occurrence of these mutated genes was correlated with the minimum inhibitory concentration (MIC) of penicillin, determined by the agar dilution test. RESULTS: The rate of penicillin resistance in S. pneumoniae in Porto Alegre, Brazil was 22.8% (16.3% intermediate resistance and 6.5% high resistance). In a statistically significant proportion of cases (p < 0.05), penicillin-susceptible samples had no amplicons, intermediate samples had only one (generally from PBP 2x), and highly resistant samples had amplicons from all three PBPs investigated. CONCLUSION: These results suggest that penicillin resistance in S. pneumoniae in southern Brazil is on the increase, but is still lower than in other countries, and that PCR could be used for its early detection.     

Concomitant high-level vancomycin and penicillin resistance in clinical isolates of enterococci.

Enterococci are important nosocomial pathogens among which resistance to multiple antibiotics is being recognized with increasing frequency. We characterized three clinical isolates from three New York City hospitals that demonstrated concomitant resistance to vancomycin (one VanA, two VanB phenotypes) and high-level resistance to penicillin. Two Enterococcus faecium strains were intrinsically highly resistant to penicillin and showed very low affinity for penicillin of penicillin-binding protein 5. Unlike previously described glycopeptide-resistant enterococci, these strains were not hypersusceptible to beta-lactam agents after vancomycin induction, and combinations of penicillin and vancomycin were not synergistic against them. A third isolate, Enterococcus faecalis, produced beta-lactamase. Two of the three strains were also highly resistant to all aminoglycosides. Emergence of concomitant high-level resistance to multiple antibiotic classes among enterococci considerably narrows the therapeutic options for treatment of infections due to these opportunistic pathogens.     

Increasing penicillin and trimethoprim-sulfamethoxazole resistance in nasopharyngeal Streptococcus pneumoniae isolates from Guatemalan children, 2001--2006.

OBJECTIVES: We aimed to determine nasopharyngeal colonization rates and antibiotic resistance patterns of Streptococcus pneumoniae isolated from Guatemalan children, and to determine risk factors for colonization and antibiotic nonsusceptibility. METHODS: Isolates were obtained from children aged 5 to 60 months attending public and private outpatient clinics and daycare centers during August 2001--June 2002 and outpatient clinics during November 2005--February 2006 in Guatemala City. Minimal inhibitory concentrations of penicillin, trimethoprim-sulfamethoxazole (TMS), cefotaxime, and erythromycin were determined using the E-test. RESULTS: The overall nasopharyngeal colonization rate for S. pneumoniae was 59.1%. From 2001/2 to 2005/6 TMS nonsusceptibility increased from 42.4% to 60.8% (p<0.05) in public clinics and from 51.4% to 84.0% (p=0.009) in private clinics, and penicillin nonsusceptibility increased from 1.5% to 33.3% in public clinics (p<0.001). Reported antibiotic use was not strictly associated with nonsusceptibility to that same antibiotic. Resistance to three or four antibiotics increased in public clinics from 2001/2 (0%) to 2005/6 (10.7%; p<0.001). Risk factors for nasopharyngeal colonization with penicillin- or TMS-nonsusceptible S. pneumoniae were low family income, daycare center attendance, and recent penicillin use. CONCLUSIONS: Increasing antibiotic nonsusceptibility rates in nasopharyngeal S. pneumoniae isolates from Guatemalan children reflect worldwide trends. Policies encouraging more judicious use of TMS should be considered.     

Antibiotic resistance of Helicobacter pylori clinical isolates in Hebei Province

<正>Objective To evaluate the resistance of Helicobacter pylori(H.pylori)clinical isolates to various antibiotics,in order to guide rational drug use in Hebei Province.Methods From January 2014 to July 2015,260 patients with H.pylori infection who had not received eradication treatment were enrolled in Third Hospital of Hebei Medical University.Gastric mucosa biopsy tissue samples     

In vitro activity of the new ketolide telithromycin and other antibiotics against Streptococcus pneumoniae in Belgium

In Belgium more than 17% of the invasive pneumococci are not susceptible to penicillin, and more than 38% not to macrolides. The most prevalent mechanism of macrolide resistance in Europe is modification of the drug target site leading to cross-resistance to lincosamides and group B streptogramines (MLSB resistance). Telithromycin is the first antibiotic of the family of ketolides, which differ from erythromycin by having a 3-keto group instead of the neutral sugar L-cladinose. We tested the susceptibility of 637 pneumococci, recently isolated from patients in Belgium, to telithromycin and five other antibiotics. Data generated by this study show that telithromycin inhibits 98.4% of pneumococci at a breakpoint concentration of 1 mg/L in spite of a high percentage (> 30%) of strains with the MLSB constitutive type of resistance. Susceptibilities to the five comparator drugs were: penicillin (81.8%), tetracycline (67.0%), levofloxacin (98.9%), erythromycin (61.5%) and clindamycin (66.6%). Consequently telithromycin looks to have considerable potential for the empiric treatment of community-acquired respiratory tract infections.     

Extremely high incidence of antibiotic resistance in clinical isolates of Streptococcus pneumoniae in Hungary

An epidemiologic survey of antibiotic resistance among pneumococcal isolates collected during 1988 and 1989 in Hungary indicated that as many as 58% of all isolates and 70% of isolates from children were resistant to penicillin. These figures surpass even the highest values reported thus far for Spain and South Africa for the same period. Almost or more than 70% of the penicillin-resistant isolates were also resistant to tetracycline, erythromycin, and cotrimoxazole and approximately 30% to chloramphenicol. Intravenous administration of ampicillin (30 mg/kg) did not interfere with the growth in the cerebrospinal fluid of three resistant strains introduced into the rabbit model of experimental meningitis. No resistant strain showed beta-lactamase activity. A representative highly resistant strain contained altered penicillin-binding proteins (low penicillin affinities and abnormal molecular sizes) and was also resistant to the lytic and killing effects of penicillin.     

Penicillin-binding protein families: evidence for the clonal nature of penicillin resistance in clinical isolates of pneumococci

In view of the worldwide emergence of penicillin-resistant pneumococci among clinical isolates it was of importance to examine a large number of strains to test the uniformity of the resistance mechanism. Among 160 clinical isolates of pneumococci (minimum inhibitory concentration [MIC], 0.005-16 micrograms/mL), susceptible strains showed a common pattern of five penicillin-binding proteins (PBPs) with high penicillin affinities (PBP 3 greater than 1A greater than or equal to 2A greater than 1B greater than 2B). PBPs 1A, 2A, and 2B (but not PBP 3) each showed distinct stepwise decreases in penicillin affinities parallel with increasing levels of antibiotic resistance. The number and molecular sizes of PBPs became variable in strains with MIC values greater than 1.0 microgram/mL; among 39 strains with a MIC of greater than or equal to 1.0 microgram/mL, 11 distinct and stable PBP patterns could be identified. Using PBP profiles, serotypes, and antibiotic resistance patterns, as well as data on isolation dates and sites, we identified at least three groups of resistant strains that showed clear indication of clonal origin.     

Vancomycin-tolerance among clinical isolates of Streptococcus pneumoniae in Mississippi during 1999-2001

BACKGROUND: In recent years, infection with Streptococcus pneumoniae has been a serious worldwide health concern. Antimicrobial-resistant S pneumoniae is increasing in incidence worldwide, posing a potentially serious threat. Resistance to beta-lactams, macrolides, and trimethoprim-sulfamethoxazole represents a major problem in the treatment of pneumococcal infections METHODS: Our laboratory conducted a survey of local resistance patterns in S pneumoniae. Clinical isolates from two separate respiratory seasons were collected from representative geographic areas in Mississippi (totaling 28 hospitals) and were tested for antimicrobial resistance to penicillin, amoxicillin, ceftriaxone, cefuroxime, azithromycin, clindamycin, tetracycline, trimethoprim-sulfamethoxazole, levofloxacin, gatifloxacin, moxifloxacin, and vancomycin using reference methods. Vancomycin-tolerant strains of S pneumoniae were initially identified as those in which the vancomycin MIC was 0.5 microg/mL. Strain tolerance was confirmed by time kill studies RESULTS: For the 1999-2000 respiratory season, 318 isolates were available for testing; for 2001-2002, 166 isolates were available. Of the 484 total isolates tested, two isolates were identified as having increased tolerance to vancomycin. A greater than 2 log10 difference in viability between the tolerant isolates and the nontolerant isolates of S pneumoniae was observed in time kill studies CONCLUSIONS: Two vancomycin-tolerant isolates of S pneumoniae were identified and characterized. Antibiotic tolerance is defined as the ability of bacteria to survive but not proliferate in the presence of an antibacterial agent. Tolerance to vancomycin is particularly significant when the incidence of penicillin tolerance or resistance is high. In addition, tolerance to vancomycin is not detected by routine in vitro susceptibility testing.     

幽门螺杆菌体外诱导耐药试验和耐药率监测

目的 抗生素耐药越来越被公认为是根除幽门螺杆菌（Hp)治疗失败的主要原因。比较根除Hp常用抗生素耐药性发生倾向和监测耐药率。方法 选用7株敏感菌株（其中2株为标准菌株）进行阿莫西林，四环素，呋喃唑酮，甲硝唑和克拉霉素5种抗生素的体外诱导耐药试验。随机选取2000-2001年间保存的165株菌株，用琼脂稀释法测定最低抑菌浓度（MIC），对上述5种抗生素进行耐药监测。结果 体外诱导试验显示，7株Hp中5株诱导出甲硝唑耐药，且可诱导倍数最高。5株诱导出四环素耐药。虽未诱导出克拉霉素耐药，但有1株可诱导倍数较高。未诱导出阿莫西林或呋喃唑酮耐药，呋喃唑酮可诱导倍数最低。耐药监测甲硝唑耐药率为49.7%(82/165)，克拉霉素为7.3%(12/165)，阿莫西林为1.2%(2/165)，四环素为2.4%(4/165)，呋喃唑酮为1.2%(2/165)。结论 Hp对甲硝唑很容易产生耐药，对克拉霉素可产生耐药，对呋喃唑酮和阿莫西林不易产生耐药。除四环素外，Hp对其他4种抗生素发生耐药的难易程度与实际监测的耐药率高低相关，这有助于预测感染Hp后抗生素耐药率变迁的倾向。     

1株高毒力型肺炎克雷伯菌临床分离株毒力及耐药性分析

目的对1株临床分离的高毒力型肺炎克雷伯菌菌株进行毒力基因及耐药基因分析,为临床复杂肺炎克雷伯菌感染的诊断及抗生素使用提供参考。方法首先使用PCR方法对该菌株进行血清学分型、毒力基因和耐药基因检测,然后利用二代和三代高通量测序平台对该菌株进行全基因组测序和序列拼接,应用生物信息学方法全面分析该菌株毒力基因及耐药基因。结果该菌株血清型为K1型,采用PCR方法发现该菌株携带wabG、uge、kfuBC、aerobactin、rmpA、magA和fimH 7个毒力基因及超广谱β-内酰胺酶耐药基因(基因型为SHV型)。高通量测序进一步发现该菌株的基因组还携带clbB、iroC和rffG 3个毒力基因。结论该肺炎克雷伯菌临床分离株血清型为K1,除了携带喹诺酮类和β-内酰胺类耐药基因外,还含有多种毒力基因,增加了治疗难度。全面分析感染菌株携带的毒力基因和耐药基因,有针对性地选择抗生素,可提高抗感染治疗的效率,减少并发症的发生。